The present invention relates to a boundary detector for performing high-speed boundary detection, and a bit-map graphic processing system incorporating the boundary detector.
Boundary detection is one of the functions required of a bit-map graphic processing system. Boundary detection is used in, for example, the painting of a designated closed region. Painting of a closed region in a conventional boundary graphic processing system of this type is performed in units of pixels, by use of an appropriate program. A typical example is an algorithm of program 3 shown in "Painting and Scan Conversion", Ono, Pixel No. 15, Dec. 1983, PP. 149-150. According to this technique, the program procedures of the microprocessor are set out in steps (1) to (4) as follows:
(1) The coordinates of a start point in boundary detection are stored in a stack; PA1 (2) If the stack is empty, execution is completed. Otherwise, the coordinates are extracted from the stack and are defined as a start point; PA1 (3) A segment including the start point is checked by referring to the right and left pixels of the start point in units of pixels, and the segment is painted; and PA1 (4) Pixels on the immediately upper and lower invention, a boundary detector is provided for performing high-speed boundary detection processing, comprising a generator for comparing input boundary condition data determined by the color of a predesignated pixel, with input image data having a predetermined unit data length, and for generating boundary data representing a comparison result, and a boundary detector for detecting a boundary pixel position from the boundary data output from the generating means, in accordance with input detection mode designation data, and for outputting boundary bit position data representing the detected boundary pixel position.
According to another embodiment of the present invention, a boundary detector is provided for performing high-speed boundary detection, on the basis of image data from a frame memory including a plurality of memory planes, which comprises a generator for generating boundary data from color image data of a predetermined unit data length, read out from the frame memory, in accordance with input boundary condition data. This color image data comprises monocolor image data, which corresponds to identical positions, for each of the plurality of memory planes of the frame memory. The present device also includes a boundary detector for detecting a boundary bit position derived from the boundary data, in accordance with input detection mode designation data, and for generating boundary bit position data representing the detected boundary bit position.
According to yet another embodiment of the present invention, a boundary detector is provided for performing high-speed boundary detection, on the basis of image data read out from a frame memory including a plurality of memory planes, which comprises a generator for generating boundary data from color image data of a predetermined unit data length, read out from the frame memory, and input mask data in accordance with input boundary condition data. This color image data comprises monocolor image data for the plurality of memory planes, the memory plane boundary data is generated for one of the plurality of memory planes to be subjected to the boundary detection processing, the mask data is generated as the memory plane boundary data for one of the plurality of memory planes not subjected to the boundary detection processing. The present device also includes a boundary detector for detecting, in accordance with input detection mode designation data, a boundary bit position derived from the boundary data generated by the generating means, and for outputting boundary bit position data indicating the detected boundary bit position.
In order to achieve the above objects of the present invention, there is also provided a boundary graphic processing system for performing high-speed boundary detection processing, comprising a frame memory for storing image data, display means for displaying the image data stored in the frame memory, a boundary detector for detecting a boundary bit position, on the basis of processing image data input thereto as units of predetermined data lengths, and for outputting boundary bit position data representing the detected boundary bit position in accordance with an input boundary detection control instruction. The present device also includes a controller for outputting the boundary detection control instruction to the boundary detecting means, in accordance with an input boundary detection instruction, as well as data concerning a predesignated pixel. The controller also reads out the processing image data from the frame memory, on the basis of a bit position of the predesignated pixel or the detected boundary bit position, and stores the detected boundary bit position when the boundary bit position data represents the presence of a boundary, and discriminates whether the stored boundary bit positions are continuous.
According to the present invention as described above, boundary detection can be performed for image data having a predetermined unit data length in the frame memory, and thus processing such as painting, which requires boundary detection, can be performed at high speed. In addition, a memory plane of interest and other memory planes can be designated in the course of boundary detection, and thus various boundary conditions can be set. Moreover, the addition of a new circuit arrangement to an existing bit-map graphic processing system realizes the present invention without the need to further modify the existing system.